Field of the Invention
The present invention relates to an organic light emitting element containing a 1,1′,3,3a,3′,3′a,4,4′,5,5′,6,6′,7,7a,7′,7′a-hexadecahydro-2,2′-bibenzo[d]imidazolidene compound and a display device.
Description of the Related Art
An organic light emitting element is an element containing an anode and a cathode, and an organic compound layer arranged between both electrodes. In the organic light emitting element, excitons are generated by recombination of holes and electrons injected from the above each electrode in a light emitting layer, which is an organic compound layer, and light is released when the excitons return to the ground state.
With the recent significant advances in organic light emitting elements, it is possible to make a slim lightweight light emitting device which has low driving voltage, diverse light emission wavelengths and high responsivity.
In an organic light emitting element, improvements in electron injection properties are important to migrate toward lower voltages in the element. As a technique to improve electron injection properties, doping metals in electron injection layers is described in Japanese Patent Application Laid-Open No. 2003-68468 and US 2002/0055015 A.
In addition, the synthesis method of a compound like 1-A is known in COLEMAN. A W. Journal of Organometallic Chemistry (1983), 250(1), C9-C14; however, there are no cases in which the compound is used for an organic light emitting element. In addition, there are cases in which a methyl group and a benzyl group are substituted on the nitrogen atoms; however, there are no cases in which an aromatic substituent such as an aryl group is substituted thereon.

The electron injection layers described in Japanese Patent Application Laid-Open No. 2003-68468 and US 2002/0055015 A have metals. This is advantageous in terms of electron injection properties; however, when these metals are used for an electron injection layer, a stable organic light emitting element cannot be obtained. This is because the metals used for an electron injection layer have high reactivity to moisture.